基于无线光通信链路噪声特性,建立了大气信道等效数学模型。针对大气湍流引起的信号起伏,对通过大气信道的四进制频移键控(4FSK)已调信号采用了同态滤波技术去噪,同态系统中线性滤波器设计了零相位数字滤波器。当信源码字长度取500时,同态滤波去噪后的信号通过过零检测进行解调,在光强闪烁指数s2σ=0.1,信噪比10 dB时,误码率达到7×10-4,滤波效果明显优于传统数字滤波器。仿真结果表明,同态滤波能有效地滤除大气信道中的乘性噪声,能够有效地抑制大气湍流,提高光通信可靠性。 Based on the noise characteristics of wireless optical communication link, an equivalent mathematical model of atmosphere channel is established. Aiming at the signal fluctuation caused by atmospheric turbulence, a homomorphic filtering technique is adopted for the quaternary frequency-shift keying (4FSK) modulated signal passing through the atmospheric channel. The zero-phase digital filter is designed by the linear filter in the homomorphism system. When the length of the source codeword is 500, the signal of the homomorphic filter denoising is demodulated by the zero-crossing detection. When the light intensity flicker index s2σ = 0.1 and the signal-noise ratio 10 dB, the bit error rate reaches 7 × 10-4 , The filtering effect is obviously better than the traditional digital filter. Simulation results show that homomorphic filtering can effectively filter out the multiplicative noise in the atmospheric channel, and can effectively suppress the atmospheric turbulence and improve the reliability of optical communication.